The U.S. Navy expends a considerable amount of effort in collecting and recording ocean water characteristics, such as temperature and salinity. Many of the oceanographic instruments utilized for collecting and recording such data are placed deep within the ocean for long periods of time. The usual arrangement for powering these instruments are batteries. When the batteries are expended the usefulness of the oceanographic instruments terminates until the batteries can be replaced. In some instances it is not practical to replace the batteries at great ocean depths. There is presently no satisfactory arrangement for in-situ recharging of batteries which are used to power oceanographic instrumentation.